Radio circuit



April 18, 1933. 5 PA 1,904,877

RADIO CIRCUIT Filed Aug. 4, 1931 H 4f-mmlugu INVENTOR 5W4"! Q-E vin BY 6 ATTORNEYG. JQ L Patented Apr. 18, 1933 nnwnnn mmnvinornosnnnn'nnw :rnzesnir i a mm omen 11' Appl icationflljednu gust i, 1931; Serial 1T9. 554,965,

This invention relates in general to im- 7 provements in radio" circuits, particularly those of the type using multi-electrode an 7 .dion. The general object of this invention is the provision of novel forms 0f radio circuits having ahigh degree of sensitivity and'selec f L ductance' is bridged by avariable tuningcontivity.

Another object of this-invention;involves radio circuits employing four electrode" audions.

These and many other objects as will ap pear from the following disclosure are se cured by means of this invention,

V This invention resides substantiallyin construction, combination, arrangement and relative location of partsall as will be more fully pointed out hereinafter.

Referring to the drawing in-which'the' same 2 reference numerals will, be used'throughout the several views to indicatethe same or similarparts g f Figure "1 shows the basic connection of a four electrode tube as employed in this invention. I r Figs. 2 and 3 showftwo formsof employing this basic connection Fig. 4 is a modified formo f circuit employ-Z ing this invention showing an audio amplifier v I V v In this form of'circuitthe anode B 'andthe 8 3 comprising two vacuum tubes in parallel; i

Fig. 5 is a modified form ofconnection em- 7 3 able resistance 17 by means of which volume ployingafive electrode tube.

As shown in Figure 1,- the invention em 3 ploys, a fourelectrode audio comprising the heatedqcathode 3 whichjrriay be .heatedjby means ofthe'heater2. i

At 3, is the usual control grid and at 'are' i interposed between the cathode and the inner anode 5. Actual experience with circuits employing this fundamental connection have 5 demonstrated that it is a circuit of consider- 'able sensitivity'and one which does not need ircuits inFig. 2,

usual evacuated vessel 1 having an indirectly continuous plates or perforated platesin the The input circuit 'eter 8 connected across the battery 7- which is any radio frequency "stages preceding 1 although they may be usedif desired;

' Thiscir'cuit has been shown inmore detail tance llwhich is grounded. This, tuning indenser 12. One terminal of-the inductance condenser unit is connected tjo the outer anode 6 and the other terminal isconnected to the cathode 3. 'The inner anode 5 is connected to the cathodeto a suitable batteryTwhich is bridged by a; potentiometer which isicon I nected to one terminal of'the primary-of the"1 audlo frequency transformerljii The' other terminal of this primary is connected to the grid 4; The arrangement in- Fig." 3 is*some-' what similar to that of Fig. 2 with the eXcep-- tion that in addition to the antenna inducitance 11 and it's tuning capacity 12, asec ond" inductance 14 bridged by a variable condenser 15 is supplied for tuning the input circuit ofv the audion. 1 M i The second tuned inductance provides a.-7 circuit of greater selectivity than that shown The circuit of Fig.4 is somewhat to that of Fig. 3 but includes further details:

grid at-are interconnected by means of a varicontrol may be effected. The anode 5 is con nected as before to the positivesideofasuitable current source but in this case the highresistancelfi is connected inseries therewith and is bridgedby means ofja fixed condenser 17The-resistanceof the resistor 16l'may'beofthef'order'of 50,000 ohms and the capacity of the condenser 17 may be ofthe. order 'of one 9 microfarad. The cathode in'ithis case isfcon nected' to the input circuit through resistance 18*which may be of theorder of 1,0O0rohnas1-k Thep'o'sitive'lead to the anode 5"is also cona nected to the'negative lead of the B; supply}? through theresistances19 and 20 in series. Resistance 19 may be of the order of'200,000 ohms and resistance 20 may be of the order of'- 50,000fohms. Resistance 20 is used asha potentiometerfrom which a variable lead ex 9 scope'of the appended "claims.

tends to the primary of the transformer 13.

The secondary of this transformer is connected to the input of two similar audions 21 and 22 connected in parallel. The outer anodes 6 are connected'together and to the secondary of the transformer. The grids 4 leads28= o-f asuitable transformer 27. A connection including a variable resistance 36) is connected from the midpoint'of the secondary-fof transformer 27 to the cathode circuit.

This circuit has been found to be highly sensitive and very selective and eliminates the necessity of employing radio frequency amplifying stages.

The modified arrangement of Fig. 5 employs three anodes in which the input circuit is connected between anode 40 and thecathode. Anode41, is connected to the cathode through the battery 44. Anode 42 isconnected to this battery through the variable tap 43. The output circuit is, connected between the grid 45 and the potent iometer 46 connected between thecathode.

and the variable lead 43.

From the above description it will be apparent that this invention resides in certain principles of construction. and operation which may be carried on strictlylimited to thedisclosure "as given for the purpose of illustration but rather to the What I seek to secure b United States Letters Patent is:

1. A radio circuit of the type described comprising in combination a multi-electrode audion including a cathode, a grid and two anodes, an input circuit connected between one anode and the'cathode, an output'circu it connected between the grid and the cathode and a connection between the other anode and the cathode. 1

2.=A radio circuit of the type described comprising niulti-electrode audion' including a cathode'an'dthree'c'old electrodes placed at relatively different distances from the cathode, an input circuit connected between the cold electrode furthest from the cathode. and the cathode, an output circuit connected between the cold electrode near the cathode and the cathode and aconnection'between" the 'other'oold electrode and the cathode.

3. .A radio circuit of the typedescribed comprising a multi-electrode audion .i-nclud ing a cathode and three electrodes placed at relatively different distances from the oathode, aninput circuit connected between the t in other physical forms and I do not therefore desire to be electrode furthest from the cathode and the cathode, an output circuit connected between the electrode near the cathode and the oathode and a connection between the other electrode and the cathode, said connection including a potential source.

4. A radio circuit of the type described comprising a multirelectrode audion having three cold electrodes and a cathode, an input circuit between one cold electrode and thecathode, a conn'eotion including a potential source between another of the cold electrodes "and the cathode, an output circuit connected between the other cold electrode and the cathode'includi'ng a potentiometer, a high resistance connected across the potential source and an output circuit connected between itheother cold electrode and the high resistance. I I

5. A radio circuit of the type described comprising a multi-electrode audion including acathode' and a plurality of 'coldelectrodes, an input circuit connected between one of the cold electrodes and the-cathode, an output circuit connected between another of the cold electrodes and the cathode means for interconnecting the remaining coldfelectrodes with the cathode, said means including a potential source, two multi-electrode audions each including three cold electrodes and a cathode, an input circuit coupled between one'c'old electrodeof eachaudion and the cathodes thereofand coupledto the output'oircuit of'said first audioman output circuit' connected between anoth'erof the cold electrodes of each of said auctions and the cathode and a connection between-the third cold electrode of each of said audions and thecatho'de. j v

6. A radio circuit as described comprising an audion having a cathode and three cold electrodes, an input circuit connected between-oneof the cold electrodes and 'the'cathode, a connection between another of the cold electrodes and the cathode including a potentialsource in series therewith, a resistance shunted across said potential source, an output circuit connected between the third cold electrode and :said resistance, and volume control means-"comprising a variable impedance connected between the cold electrode in the input circuit and the cold electrode-in the output circuit. 7

In testimony whereof .I have hereunto set my'hand-on this30th day of July A. D., 1931. 1 EDWARD G. PARVIN. 

